On Mon, 17 Nov 2008 10:02:59 +0100
Ingo Molnar <email@example.com> wrote:
Ah, I see. I misunderstood what you meant.
Yes, you are right. But it's pretty hard to hit this bug since x86_64
rarely uses swiotlb_alloc_coherent. pci-swiotlb_64.c tries
dma_generic_alloc_coherent first and then, only if it fails, it uses
swiotlb_alloc_coherent. dma_generic_alloc_coherent usually succeeds.
Before removing the GFP_DMA hack (the dma_alloc_coherent rewrite),
x86_64 rarely used swiotlb_alloc_coherent too because
swiotlb_alloc_coherent was used only if dma_alloc_coherent fails.
This issue was hidden by dma_alloc_coherent and GFP_DMA hack.